Process of manufacturing sodic-silico aluminate and hydrochloric acid.



A. H. GOWLES. PROUESS OI' MANUFACTURING SODIG-SILICO ALUMINA'I'E AND IIYDROGHLORIG GID.

APPLICATION FILED'OOT. 8, 1909.

MLQ., l Patented 0015. 15,1912.

lllllnn ermee Partnr onirica.

LFRED H. COWLES, yOF LOCSKPORT, NEW YORK, ASSIGNOR T0 THE ELECTRIC SMELT- ING AND ALUMINUM COMPANY, OF LOCKPORT, NEW YORK, A CORPORATION F ILLINOIS.

,v PROCESS OF MANUFACTURING SODIC-SILICO ALUMINATE AND HYDROCHLORIC ACID.

Sipecication of Letters Patent.

rateareuoet. rancia.

Application filed October 8, 1809. Serial No. 521,692.

To all whom 'it may concern.'y

Be it known that I., ALFRED H. CoWLEs,

la citizen of the United States, residing at Lockport, in the 'county of Niagara and State of New York, ha\ e invente'd a certain new and useful Improvement in the Process of lllanufacturing Sodicilico Aluminate and IIydrochloric Acid, of which the following is a full, clear, and exact description.

The present invention relates to the manufacture Aof sodic-silico-aluminate and hydrochloric acid. l

' The object of the invention has been t0 improve the manufacture of these compounds so that less time shall be consumed in the Work and richer and more unlformv products shall result. v

The above objects it will be seen are attained by the process described in the following specication, in connection' Wlth which lmay be used the charge mixture disclosed in my companion application ASerial No. 521,691, filed October 8th, 1909.A

It has-long been known that silica as .well as alumina, or both combined, Will, in the presence of steam, vor4 vapor of Water, decompose. alkali chlorids at an elevated temperature. The alkali oXid formed combines with silica or alumina, or both, as the case may be, While the chlorin unites with the hydrogen of the Water vapor to form lhydrochloric acid. Many methods have been devised to utilize this reaction to build up a practical technical process and methods di rected to this purpose appear in U. S. Patent No. 376,409, January 10, 1888 Kayser,

and the English Patent 2050 of 1862. These processes, however, ,have not foundsuccessful application, on account of certain inherent defects. My present method, hoW- ever, which forms the subject of this application, is one resulting in greater uniformity in and control over the resultant products and attended by greater rapidity vof conversion.

I mix together the solid materials used in the process, which comprise compositions containing silica and alumina, which may be associated with more or less soda or potash clieniicaily combined. Examples of such compoundsare clay, bauxite, shale, carboniferous shale, slate and the feldspars.` Along with these silica and alumina compounds I placed in the mass, ordinarily amounting i to from 3 to l() per cent. of the charge mixture the only. object of said carbon being to burn out and leave the sodic-silicoalu1ni nate porous and accessible to the gases. EX-` amples 'of such carboniferous material are anthracite coal, coke, charcoal, carboniferous shale,`bituminous coal and also sawdust. I should prefer that in the massthus obtained l5 to 55 per cent. should be alumina and from 30 to per cent. should be alkali chl'orid. The mix is then formed in loriquets and placed in a suitable down draft furnace. The steam, air andfuel gases, from oil, gas or powdered coal, are admitted from above and the Waste gases together with vapor of Water and the hydrochloric gas formed are drawn olf from the bottom.

The necessary amount, by Weight, of Sodium chlorid, is substantially twice the weight of sodium oxid necessary for reaction with the clay. 'This necessary orpermissible quantity of sodium oxid that can be employed with the clay, Varies Withthe composition ofthe clay, the magnitude of the operation and the 'amount of carbonaceous matter that can be incorporated with the clay, Without supplying the furnace with` tions of operation and with varying compositions of materials. p

Under the influence of an oxidizing at- Inosphere the carbon in the body of theY lumps or briquets will burn, rendering them porous and more easily heated and penetrable by the envelopinggases. l more, the very presence of the carbon as 1t burns away enables me tomaintain an oxidizing atmosphere surrounding the partially transformed-briquets or masses within the Further-V 'the alkali chlorid;

furnace during the operation, because of using less gaseous fuel and thus preventing the reduction ofthe alkali oxid after it has been formed by the action of the steam upon rl`hus the' alkali oxid is retained united with the 'silica and alumina present, in the form of sodic-silico-ahuninate. rlhe use of carbon in the bricks makes it possible to use a less and therefore cheaper fuel flame for raising the temperature. Further, the carbon when burning decomposes 'a portion of the steam or vapor of water; and consequently the hydrochloric acid gas formed in the reaction between the undecomposed steam and the alkali chlorid will pass oft in a more concentrated condition and be more easily and less expensively collected. At the finish of the treatment it' i lWill be found that the oxidation of the carbon leaves the briquets or balls porous and friable and more readily subject to such opening processes as may be used for the purpose of obtaining the alumina, and alkali.

The temperature for obtaining the best results depends upon the quality of the mixture, varying from 17 00 to 2400 Fahrenheit, according as the percentage of alumina in the mixture is increased or diminished. The higher' the alumina content, the hotter the temperatureemployed, the higher the percentage in silica, the lower the temperature of reduction.

The determining factors as to the length of the process are the rates of progression of heat and steam from the surface to the interior of the bricks. has heretofore been so slow as to cause the zone'of action to proceed down the furnace at a comparatively slow rate with the ultimate result that a large part of the salt which is volat-ilized has been carried forward to the bottom of the furnace and deposited in a zone Where reaction Was not possible. I have discovered, however, that by carrying on the process with carboniferous material contained inthe mass of the bricks, that the reaction will proceed far more rapidly and with far better control and greater' uniformity than has heretofore been possible.

By reason of the carbon being in the body of the bricks and the combustion taking place therein at the same time that the exterior flame is being applied, the bricks will be raised to the proper temperature for reaction. quickly and with much less volume of gaseous fuel than is possible otherwise. This results in the hydrochloric acid gas formed passing oit in a more concentrated condition and therefore more easily and less expensively. handled and collected. l Further, hy reason of the burning of the carbon in the mass of the bricks, it is possible to supply a large proportion of air along with the gaseous fuel without lowering the temperature Their penetration.'

and yet maintaining an oxidizing atmosphere within the furnace. The maintenance of this oxidizing atmosphere is a distinct advantage, since it prevents the escape downward of sodium or volatile aluminum chlorid through their immediate oxidation at the high temperature. Under non-oxidizing' conditions there is liable to resulta carrying forward of the aluminum chlorid and the sodium, which are deposited in various .forms in the lower part of the furnace. burning of" the carbon in the bricksleaves them more porous and easily penetrated by the steam, so that reaction proceeds more rapidly. This is av decided advantage since Finally, the. l

one of the greatest drawbacks to the previous method of procedure has been the extreme slowness with which any resultsare accomplished. The sodic or Silico# sodio aluminate that can be made by this process may be made completely free from iron as ydesired means.

When the carbon is mixed in with the laluminous minerals and saltI in thev body of the lumps, that make up the charge, the

resultant product can be produced white and l perfectly free from all ironAv impurities..A y Hence I consider such a method of adding my carbon preferable to that of first making mixtures of clay and salt andwith the blocks or lumps so made, mixing fragments of coal or coke to make up the charge. Where the charge contains such separate fragments of 'los coal, I have found that iron oxid accumuv lates from impurities in the aluminous minerals employed, but such a charge mixture, other than giving me a less white and friable product, works the same as but much slower than in the case where the carbon is contained within the body of the lumps of the mixture. i

I In the accompanying drawing showing, by way of example only, an apparatus in which my process can be carried out, A represents a gas producer in which is contained the fuel, such as gas coke, etc., a is the pipe supplying steam to the generator A, b is `the pipe connecting the'generator A with the blower C, which draws off the gas from the generator and discharges it through the pipe d into the combustion chamber D, into' which air is forced by the fan E, through the hydrochloric acid fumes pass to the' acidv tower K.

J is the base of the tower; K coke, or similar materials uponl which the' acid fumes steam, and maintaining an oxidizing atmosmixed with condensed. l By the improvements above described I have, rendered the production of sodic-silico aluminate and hydrochloric acid commercially practical both by reason of the shortwater from the pipe M are 1' ening of the time ofthe process, securing more concentrated hydrochloric acid fumes and by the' uniformity of results secured, the latter being due in part to the rapidity of the process itself and the dimin'- ished volume of gas required.

The blocks of alumina, silicious matter, salt and carbonaceous material herein described areclaimed in my copending application, Seriall No. 521,691, tiled October 8, 1909, and in my application Serial No. 637 ,346, led July '7, 1911.

Having described my invention, I claim: l. The herein vdescribed method which comprises treating a char e mixture consist ing of an alkali chlori a carboniferous material and a composition containing silica and alumina, at a high temperature, with steam and air.

2. The herein described method which comprises treating a charge mixture consisting of an alkali chlorid, a carboniferous material and a composition containing silica and alumina, at a high'temperature, with phere in the reacting zone.

3. The herein described method which comprises treating a charge of lumps composed of an intimate mixture of an alkali chlorid, a carboniferous material and a composition containing silica and alumina,

ata high temperature, with steam and air.

et. rPhe herein described method which comprises treating a charge mixture consisting of a charge of lumps composed of an intimate mixturepf an alkali chlorid, a carboniferous material and a composition con taining silica and alumina, at a high tem`\ perature, wlth steam, and maintaining an oxidizing atmosphere surrounding said lumps in the reacting zone. ,i

5. The herein described method which comprises treating an alkali chlorid, a carboniferous'material and a composition containing silica and alumina, at a high temperature, with steam and air, the alkali chlorid being substantially between, 30 and per cent., the carboniferous material between 5 and l0 per cent. and the alumina.

lkali-silico-aluminate, which i signature in the presence of two Witnesses. y

ALFRED H. COWLES. lVitnessess J. M. WooDwAnD,

R. SULLIVAN. 

